Catheters are flexible medical instruments that facilitate withdrawal and introduction of fluids from and to body cavities, ducts, and vessels. Catheters can be used, for example, in hemodialysis procedures. During some hemodialysis procedures, a multiple lumen catheter having an arterial lumen and a venous lumen is inserted into a subject's body. Blood is withdrawn through the arterial lumen of the catheter, and the removed blood is directed to a hemodialysis machine that dialyzes the blood to remove waste and toxins. The dialyzed blood is then returned to the body through a venous lumen of the catheter.
Some hemodialysis catheters include a staggered tip design in which an arterial inlet is upstream of a venous outlet to increase the likelihood that blood returning to a subject through the venous outlet will be expelled downstream from the arterial inlet. In use, such staggered tip hemodialysis catheters can become occluded as a result of fibrin sheath formation, thrombus formation, and/or the position of the hemodialysis catheter relative to a vessel wall (positional occlusion). Poor flow resulting from these conditions can limit the efficiency and/or effectiveness in delivering dialysis treatment to a subject. Common measures used to resolve occlusion of staggered tip hemodialysis catheters include reversing the blood lines of the catheter to the hemodialysis machine. While often effective in reestablishing flow, reversing the blood lines of a staggered tip catheter can itself adversely impact efficiency of the hemodialysis treatment as a result of expulsion of cleaned blood upstream of the point of intake of blood to be treated. Upstream expulsion of cleaned blood increases the potential for clean blood to be drawn back into the catheter, a condition referred to as recirculation, which decreases efficiency of dialysis by increasing treatment time to reach prescribed blood cleanliness levels.